🌡️ Temperature Conversion Calculator
Quick Summary
- Instant 3-way conversion: Celsius (°C) · Fahrenheit (°F) · Kelvin (K) — type in any field, all update in real-time
- Real-world examples: Cooking temperatures, weather comparisons, medical/fever reference ranges
- Complete formula reference: Step-by-step conversion equations with worked examples
- Key reference points: Freezing / boiling / body temp / absolute zero in all three scales
Convert Celsius · Fahrenheit · Kelvin
Type a value into any field below — the other two convert automatically. 100% client-side, works offline.
💡 Tip: For rough weather estimates: °F ≈ °C × 2 + 30 (add ~30 instead of 32, double instead of ×9/5 — close enough for planning!).
🌍 Real-World Temperature Examples
Practical reference temperatures organized by everyday life scenarios — cooking, weather, and medical/health.
Cooking & Baking
Weather & Climate
Medical & Body
📐 Conversion Formula Reference
Complete set of exact equations for converting between Celsius, Fahrenheit, and Kelvin — each with a worked example.
| Convert | Exact Formula | Step-by-Step Example |
|---|---|---|
| °C → °F Celsius to Fahrenheit |
°F = °C × 9/5 + 32 |
20°C → °F
= 20 × 9 ÷ 5 + 32 = 36 + 32 = 68°F |
| °F → °C Fahrenheit to Celsius |
°C = (°F − 32) × 5/9 |
68°F → °C
= (68 − 32) × 5 ÷ 9 = 36 × 5 ÷ 9 = 20°C |
| °C → K Celsius to Kelvin |
K = °C + 273.15 | 20°C → K = 20 + 273.15 = 293.15 K |
| K → °C Kelvin to Celsius |
°C = K − 273.15 | 293.15 K → °C = 293.15 − 273.15 = 20°C |
| °F → K Fahrenheit to Kelvin |
K = (°F − 32) × 5/9 + 273.15 |
68°F → K
= (68−32) × 5 ÷ 9 + 273.15 = 20 + 273.15 = 293.15 K |
| K → °F Kelvin to Fahrenheit |
°F = (K − 273.15) × 9/5 + 32 |
293.15 K → °F
= (293.15−273.15) × 9 ÷ 5 + 32 = 36 + 32 = 68°F |
🔬 Key Temperature Reference Points
Scientific and everyday landmarks across all three temperature scales (at standard atmospheric pressure).
| Reference Point | 🌡️ Celsius (°C) | 🔥 Fahrenheit (°F) | ⚛️ Kelvin (K) |
|---|---|---|---|
| 🥶 Absolute Zero (theoretical coldest) | −273.15 | −459.67 | 0 |
| ❄️ Water Freezes (sea level) | 0 | 32 | 273.15 |
| 🧊 Freezer Setpoint | −18 | 0 | 255.15 |
| 🧊 Fridge Setpoint | 4 | 39 | 277.15 |
| 🏠 Comfortable Room Temp | 20–22 | 68–72 | 293–295 |
| 🫀 Average Human Body Temp | 37.0 | 98.6 | 310.15 |
| 😷 Fever Threshold (Adult) | 38.0+ | 100.4+ | 311.15+ |
| 🍳 Typical Hot Tap Water | 49 | 120 | 322.15 |
| ♨️ Water Boils (sea level) | 100 | 212 | 373.15 |
| 🍪 Oven — Moderate Bake | 180 | 350 | 453.15 |
❓ Frequently Asked Questions
How do I convert Celsius to Fahrenheit in my head?
For a quick rough estimate: double the Celsius, add 30. (Exact is ×9/5 + 32.) Example: 20°C → 2×20+30 = 70°F (actual: 68°F — close enough for weather). Reverse estimate: (°F − 30) ÷ 2.
Why do we have three different temperature scales?
Fahrenheit (°F) (1724): German scale where 0° was the coldest salt-water brine Fahrenheit could make, 96° approx. body temp. Common in the US, Bahamas, Belize, Cayman Islands. Celsius (°C) (1742): Swedish scale with 0° = water freezes, 100° = water boils. Used nearly everywhere else. Kelvin (K) (1848): Absolute thermodynamic scale used in science & engineering, starts at absolute zero (0 K = no thermal motion).
What temperature should I set my oven in °C vs °F?
Common oven settings: Slow/Low = 150°C / 300°F, Moderate = 180°C / 350°F (the most common baking temp), Moderately Hot = 200°C / 400°F, Hot/Roast = 220°C / 425°F. When converting recipe books, round to nearest 25°F or 10°C for practicality.
Is 37°C (98.6°F) still the "normal" body temperature?
The classic 37.0°C / 98.6°F comes from a 1868 study by Wunderlich. Modern research (e.g., Stanford 2017, BMJ 2020) finds the average adult closer to 36.6°C (97.9°F), likely due to lower infection rates and lower metabolic rates. The fever threshold of 38.0°C (100.4°F) remains clinically standard.
Does the boiling point of water change with altitude?
Yes. At higher elevation, atmospheric pressure drops, so water boils at a lower temperature: Denver (1610 m / 5280 ft) = ~95°C (203°F), Mexico City (2240 m) = ~93°C (199°F), Everest Base Camp (5364 m) = ~82°C (180°F). Pressure cookers raise the pressure so water boils hotter (≈120°C / 248°F), speeding cooking.